Are any of these servers what you are looking for?

Servers with "left4dead" and "Valve" in the name:
Valve Left4Dead Server #18 (srcds154.vie-1.valve.net)
Valve Left4Dead Server #31 (srcds154.lux-3.valve.net)
Valve Left4Dead Server #33 (srcds154.lux-3.valve.net)
Valve Left4Dead Server #47 (srcds154.lux-3.valve.net)
Valve Left4Dead Server #13 (srcds154.lux-3.valve.net)
Valve Left4Dead Server #54 (srcds154.lux-3.valve.net)
Valve Left4Dead Server #56 (srcds154.lux-3.valve.net)
Valve Left4Dead Server #37 (srcds154.lux-3.valve.net)
Valve Left4Dead Server #9 (srcds154.lux-3.valve.net)
Valve Left4Dead Server #25 (srcds154.lux-3.valve.net)